arrogant?

The "You're All Wrong" bumper-sticker I posted a few days ago may strike some as atheist arrogance, but consider that the Christian version would look like this,

the Jewish one like this,

and the Muslim one like this:

Many freethinkers have observed that atheists merely believe in one fewer god than do (most) theists; Richard Dawkins said it well:

I have found it an amusing strategy, when asked whether I am an atheist, to point out that the questioner is also an atheist when considering Zeus, Apollo, Amon Ra, Mithras, Baal, Thor, Wotan, the Golden Calf and the Flying Spaghetti Monster. I just go one god further.
(The God Delusion, p. 77)